Displacement pump



May 8, 1951 D. T. JAMES ET AL 2,551,605

DISPLACEMENT PUMP Filed Dec. 3l, 1948 3 Sheets-Sheet l /m/fA/raes May11951 D. T. JAMES ET AL 2,551,605

DISPLACEMENT PUMP Filed Dec. .'51, 1948 3 Sheets-Sheet 2 May 8 1951 D.T. JAMES ET Al. 2,5514605 DISPLACEMENT PUMP Filed DSC. 31, 1948 3SheetS-Slleel'I 3 Patented May 8, 1951 DISPLACEMENT PUMP David T. James,Middletown, and Arthur J. Rawson, Rocky Springs, Md.

Application December 31, 1948, Serial No. `68,708

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) 5 Claims.

This invention relates to pumps, particularly t an improved positivedisplacement pump in which an eccentric member compresses :an elastictube to expel the contents of the tube.

The invention described herein may be manufactured and used by or forthe Government, for governmental purposes, without the payment to us ofany royalty thereon.

Prior pumps of this type had several disadvantages. The compressingmember set up severe strains and distortions in the tube member.Disintegration of the tube was hastened by frictional or abrasiveaction, with resultant excessive maintenance and replacement costs.

The primary object of the present invention is to improve theconstruction, assembly, and operation of a pump oi the type describedherein. Another object is to provide such a pump in which standardrubber tubing can be employed. A further object is to provide such apump that is capable of delivering an exact measured quantity of fluid,as required by the automatic inoculating apparatus described in theco-pending application of John C. Wagner and David T. James, ledDecember 16, 1948, Serial Number 65,542.

Other equally important objects will more plainly appear from thedetailed specication and drawings herein presented in exemplication butnot in limitation of the present invention. Like reference charactersrepresent like parts of a preferred embodiment of the present invention,shown in the accompanying drawings which illustrate diagrammatically in:

Figure l; an isometric view of the assembled pump mechanism withportions shown broken away, for clarity.

Figure 2; an isometric View of the pump core showing the tubearrangement and the inlet and outlet path for the iluid.

Figure 3; a vertical longitudinal cross-sectional view taken on theplane 2, 2, 2, 2 of Figure l.

Figure 4; a vertical transverse cross-sectional view taken on the plane3, 3, 3, 3 of Figure 1.

As shown in Figure 2, elastic tubing 22 leads from container 2l andenters core 23 through inlet aperture 36, then out of slot 2 and aroundcore 23 for more than one turn, and then into slot 25 and out of outletaperture 26.

As shown in Figure 3, lcore 23 is joined to iixed shaft I by suitableattaching means such as bolt or screw 28.

As shown in Figure 4, outer ring I2 is rotated on shaft I5 by means ofdriving pinion 3| and driven gear 32 which is fixed to ring I2.

External ring or driven shell I2 contains an eccentric pocket 3i).Internal ring II is adjustably mounted in pocket 30. Internal ring II'contains an eccentric pocket 40. Roller bearing I9 is mounted in pocket40, and compressor ring 29 is mounted for free rotation in iloatingconcentric contact with the internal circumference of bearing I0, andfree floating eccentric contact with the outwardly disposed externalwall of tube 22, and is arranged to progressively collapse tube 22inwardly against core 23, when in Vopera.- tion, as shown in Figures land 3.

The iamount of eccentricity aiorded by pocket 40 is controlled by therotational adjustment of ring II in pocket 3D. This adjustment is madeby first loosening screw I4 and thus releasing lock nut i3. This permitsthe relative adjustment to be made by turning ring I I by hand.Thereafter ring lI is clamped into its new adjusted position bytightening screw I4 and thus pulling lock nut I3 back into its lockingposition in its housing formed by groove I6 in ring I I, and by grooveI1 in ring I2, as shown in Figures 3 and 4.

This permits adjustment to suit varying thicknesses of tubing. It alsopermits adjustment to a concentric position so that the assembly of core23 and tubing 22 in the pump 20 can thereby be greatly facilitated.

Within the limits of the range from concentricity to maximumeccentricity, it is apparent that an infinite number of adjustments maybe made. This affords accurate adjustment for tubes of various internaldiameters and thereby provides means for accurately metering the amountof fluid delivered by one or more, or by fractional, revolutions of pump20. This arrangement is particularly valuable when used in conjunctionwith the revolution controlV mechanism described in co-pendingapplication of David T. James, filed December 31, 1948, Serial Number68,707, which matured into Patent N0. 2,537,673 dated January 9, 1951.

In operation, power may be applied to drive pinion 3|. This rotatesdriven gear 32, and external ring I2, around fixed shaft I5, and core 23which is joined to shaft I5.

Internal ring I'I is locked to external ring I2 as explained herein, androtates with roller bearing I0, ring I2 and gear 32, around core 23, inthe direction shown by the arrows in Figure 1. As ring 29 is free torotate within roller bearing I0, it applies practically frictionlesspressure inwardly on tube 22, as there is no relative sliding orslipping movement between tube 22 and ring 29. Any tendency to slide orslip is overcome by the action of roller bearing I0 on ring 29. It isim-l portant to note at this point that the inward pressure of ring 29on tube 22 compresses tube 22, which also reduces internal friction andwear on tube 22, as compared to prior pumps that apply outward pressurewhich acts to stretch the tubing and thereby increases the rate of wearthereon.

From the foregoing it becomes apparent that standard rubber or otherelastic tubing may be employed, because the stationary core 23 holds thetubing in place without anchoring along one or more elements of thetubing, as shown in prior U. S. Patent No. 2,414,355, to BorisBogoslowsky, issued January 14, 1947. Anchoring of Vam'pt'ype willinescapably cause longitudinal shear which critically increases wear.

The present invention permits normal collapsing only, which also removesanother cause of wear in prior pumps.

It is also apparent that core 23 may readily be removed from, orinserted in, pump 2) by means of the attaching bolt or screw 28. Thispermits rapid changing of tubing 22 to tubing of a different Iinternaldiameter when it is desired to change the capacity of pump 2D. With aVpredetermined internal diameter of tube 22 and a predeterminedeffective length of tube 22, the volume of uid delivered per revolutionof pump 2l!- is easily determined.

With the direction of rotation as indicated by the arrows in Figures 2and 4, iiuid may be pumped from container 2| through tube 22 at inletaperture 36 and at outlet aperture 26 where the fluid is ejected at thedelivery end 21 of tube 22, as shown in Figure 1. A reversal of rotationreverses the direction of flow just described.

While a preferred embodiment of the present invention has beenillustrated in the lforegoing specification, it is not intended to belimited thereto but it is contemplated that it includes vallmodifications and embodiments within the spirit and scope of theappended claims.

We claim:

l1. A pump comprising: a cylindrical core removably xed to a stationaryshaft; a length of elastic tubing wrapping around the cylindricalsurface of said core; inlet and outlet means for said tubing; a sourceof uid in communication with said inlet means; an external driven ringmounted for rotation about said core; means or driving said driven ring;a rst eccentrically i disposed cylindrical pocket in said externalring;'an internal ring mounted in said first pocket and attached to saidexternal ring for rotation about said core; means for rotativelyadjusting said internal ring in said first pocket; a second eccen'-trically disposed cylindrical pocket in said internal ring; a rollerbearing mounted in said second pocket and attached to said internal ringfor rotation about said core; a freely rotatable compressor ring mountedfor iioating concentric contact with the internal circumference of saidroller bearing and for floating eccentric contact with the outwardlydisposed external wall of said length of tube; said core and said tubebeing positioned in cooperating relationship with said compressor ringwheieby in operation said compressor ring will progressively collapsesaid length of tube inwardly against said core.

2. In combination in a pump of the class described: a xed cylindricalcore; a length of elastic tubing entirely encircling said core; andmovable compressor means encircling said core and adapted to be movedeccentrically thereon for progressively collapsing said tubing inwardlyagainst said core.

3. In combination in a pump of the class described: a fixed cylindricalcore; a length of elastic tubing around said core; inlet and outletmeans for said tubing; a source of fluid in communication with saidYinlet means; an external eccentric member and an internal eccentricmember arranged for rotation about said core; a ring arranged for freelyiioating concentric contact with said internal member and for freelyfloating eccentric contact with said length of tubing, whereby said ringwill progressively collapsesaidlength of tubing inwardly against saidcore, in operation, and thereby expel said fluid through said outletmeans.

4. The combination of claim 3 that includes: means for readily removingand replacing said core, whereby said tubing may be replaced with tubingof a diierent diameter; means for rotatively adjusting the position ofsaid internal member with respect `to the position of said externalmember, whereby said ring will be in floating eccentric contact withtubing of said different diameter.

5. The combination of claim 3 that includes: an annular frictionreducing member positioned between said ring and said internal member.

DAVID T. JAMES. ARTHUR J. RAWSON.

REFERENCES CITED The following references are oi' record in the file oflthis patent:

UNITED STATES APATENTS Number Name Date 2,015,574 Webb Sept. 24, 19352,414,355 Bogoslowsky Jan. 14, 1947 2,537,673 James Jan. 9, 1951

